686429617 has 4 divisors (see below), whose sum is σ = 686502756. Its totient is φ = 686356480.

The previous prime is 686429599. The next prime is 686429629. The reversal of 686429617 is 716924686.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 716924686 = 2 ⋅358462343.

It can be written as a sum of positive squares in 2 ways, for example, as 64625521 + 621804096 = 8039^2 + 24936^2 .

It is a cyclic number.

It is not a de Polignac number, because 686429617 - 2⁷ = 686429489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686429647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19984 + ... + 42097.

It is an arithmetic number, because the mean of its divisors is an integer number (171625689).

Almost surely, 2^686429617 is an apocalyptic number.

It is an amenable number.

686429617 is a deficient number, since it is larger than the sum of its proper divisors (73139).

686429617 is a wasteful number, since it uses less digits than its factorization.

686429617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73138.

The product of its digits is 870912, while the sum is 49.

The square root of 686429617 is about 26199.8018503957. The cubic root of 686429617 is about 882.1288065405.

It can be divided in two parts, 6864 and 29617, that added together give a square (36481 = 191²).

The spelling of 686429617 in words is "six hundred eighty-six million, four hundred twenty-nine thousand, six hundred seventeen".